Os calsis prosthesis



FIG. 1 is a bottom plan view of an os calsis prosthesis;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a rear elevational view thereof; and

FIG. 6 is a perspective view thereof as viewed from the rear. 

The ornamental design for an os calsis prosthesis, as shown and described. 